Currently, kml2gmt just convert the data format, but should instead build a dataset structure, and if -Fp is active then determine if any of the polygons are holes or the others and set the -Ph multisegment flag.

History

The solution has instead been implemented in gmtspatial whose -Sh option will reorganize a set of polygon, detect which ones are holes, and set the appropriate multisegment flag. So users of kml2gmt digitizing polygons should run their results through gmtspatial.